Search Documents

By Robert T. DeGavre

I have been asked by the Society of Mining Engineers to present a paper on Inco Limited's Indonesian nickel project as a case study in the financing of large overseas mining projects. I welcome this opportunity It is a story worth telling not only because the project itself represents a significant human achievement but also because there are certain important lessons that can be derived from our experience in financing the project. The paper will be divided into four sections: (i) a brief history of the project, (ii) a critical appraisal of the project's financing plan in terms of the goals that we sought to achieve, (iii) some comments on certain factors underlying the relative success of the financing plan, and (iv) the contributions that the engineering staffs must make to a successful financing plan. The paper will not present a technical assessment of the project since Inco Limited has been asked to submit a series of papers on this subject at the International Laterite Symposium as part of the 108th Annual Meeting of the AIME in February 1979.

Jan 1, 1978

By John C. Niedzielski

The existing US-70 Bridge over the Gila River at Bylas, Arizona is planned to be replaced due to its current poor condition. The replacement bridge is planned to be a 15-span, 1,904-foot (580 meter) long bridge, the third-longest bridge in the state highway system. Within the Gila River floodplain, granular alluvial soil is underlain by cohesive lacustrine soil; bedrock was expected due to nearby terrain but not encountered within the geotechnical exploration depth of 166.5 feet (51 meters) or less. Based on the anticipated loading conditions, design scour depths and the soil conditions, the full structural loads are carried by large diameter drilled shafts; therefore accurately determining the axial capacity of the proposed drilled shafts has important practical and safety implications. The conventional methods for axial capacity determination may be overly conservative to use for design in the site?s layered granular and hard clay soils. An Osterberg cell load test was performed to obtain detailed information on the load transfer from the drilled shaft in side friction and base resistance to allow optimization of the bridge foundation design. The full-scale field test played a significant role in the design of the project?s deep foundations, notably, by incorporating the specific subsoil properties and consequently, an exact prediction of the load-settlement behavior under loading. This paper provides the results of the geotechnical site investigations, drilled shaft load testing procedures, and shaft load distribution from the load test results. Comparisons were developed between predicted axial capacities of drilled shafts using several design methodologies and the axial capacity measured from static load testing. The load test results showed that underestimation of the axial capacity is evident using conventional methodologies. The exact prediction of the load-settlement behavior under loading combined with a site-specific design approach, resulted in a substantial reduction of foundation costs due to reduced drilled shaft dimensions.

By George H. Holmes

The water situation in Nevada mineral and related industries is described in this report. It contains information on the sources and adequacy of supply to current operators, requirements and uses, quality and costs, geography, hydrography, precipitation and evaporation characteristics, and Nevada water laws. Also, information is given on the water requirements of one public utility powerplant, and the source and consumption of water in four major cities. Water distribution at 24 operations is shown on schematic waterflow diagrams. The mineral industries of Nevada in 1962 used 8.6 billion gallons of nee' water and reused 3.8 billion gallons for a total usage of 12.4 billion gal¬lons. The copper industry was the major water user. The 1962 value of all mineral production in Nevada was $85.5 million. The large amount of water required to maintain this high production is obtained principally from ground-water sources in alluvial valleys and the permeable rock formations of some mountain ranges. Some water is also obtained from perennial streams and springs. Sources of water utilized by existing industry ore near most mineral industry operations; however, seven companies are forced to pipe water distances ranging from 2 to 8 miles. Although water supplies of presently operating companies are adequate at most operations, several companies resort to large-scale reuse of water as a matter of conservation and economics. Acquisition of water by new operators is possible but takes considerable negotiation. Water rights, surface and underground, are controlled by the State. The quality of the water is satisfactory for most purposes. Analyses of 19 samples, listed in the appendix, show the range in water quality at various plants throughout the State. Costs of delivering new water to current operations range from 2 to 26 cents per 1,000 gallons with an average of 10 cents per 1,000 gallons for power and maintenance. No firm costs for recirculating water were available; estimated costs range from 1.5 to 2.5 cents per 1,000 gallons. The mineral-product value of the entire Nevada mineral industry in 1962 was equivalent to $10 per 1,000 gallons of new water and $26 per 1,000 gallons consumed. Projection of the 1962 water requirements of the Nevada mineral industry indicates that the demand for new water will increase from 8.6 billion gallons in 1962 to 11.9 billion gallons in 1980, a 43-percent increase. Water requirements ill the year 2000 are estimated as 14.8 billion gallons, an increase over 1962 water demand of 78-percent.

Jan 1, 1966

By T. Emery, D. Sweet, J. Bourgeois, B. Seymour, D. Porter

Cemented rockfill (CRF) is being used to backfill primary and secondary stopes at the Eagle Mine, an underground nickel and copper mine operated by Lundin Mining. National Institute for Occupational Safety and Health (NIOSH) researchers from the Spokane Mining Research Division (SMRD) are conducting cooperative research with the mine staff to determine if the size of a CRF sample affects its measured strength properties. Based on previous research by NIOSH, cylindrical samples of CRF ranging in size from six to eighteen inches in diameter were cast at the mine and cured underground. The samples were later transported to the SMRD laboratory and the Michigan Technological University where tests were conducted to determine the strength and elastic properties of the CRF. To further analyze the relationship between backfill density and compressive strength, different ASTM International compaction techniques were used to cast the samples. For comparison, tests were also conducted on in-situ core samples that were drilled from a stope which had been backfilled with the same CRF mix. The data collected from this study not only improves our understanding of CRF in-situ properties but also helps optimize Quality Assurance/Quality Control (QA/QC) methods for backfill preparation and testing.

Feb 1, 2023

By C. M. Rule, A. K. Anyimadu, L. Knopjes

Ongoing development work on ultra-fine grinding for various applications at the Group?s concentrators has been conducted by Anglo Platinum over the last few years. Current potential applications for mainstream grinding and concentrate grinding are the subject of a group-wide research and development programme. The first 10 000-litre 2.6 MW IsaMill was jointly developed by Anglo Platinum, Xstrata Technology and Netszch for installation at the Western Limb Tailings Re-treatment project in Rustenburg, South Africa. The unit was commissioned in late 2003/early 2004, and has operated in an intermediate concentrate regrind application successfully since. This paper describes the operational performance to date, as compared with the original duty specifications and objectives. The first mainstream M10 000 IsaMill with a 3 MW drive will be operational in November2006 at the Potgietersrus Platinum (PPL) ?Platreef? Sandsloot Concentrator in South Africa?s Limpopo Province. Key Words: Western Limb Tailings Re-treatment Plant, IsaMilling, Platreef, Platinum, Palladium, PGMs, tailings.

Jan 1, 2006

By F. W. Maclennan

The following is a list of members who died in 1929. It is compiled from reports to the Secretary's office. Biographical sketches published in Mining and Metallurgy are indicated in the last two columns. Issue Containing Year of Date of Biography Election Name Death 1929 Page 1922 Adams, Waldo Peck................................ June 2 September 435 1903 Argall, Joseph.................................... Nov. 1 1894 Austin, Leonard S................................. Oct. 30 December 580 1905 Bailed, Melbourne.........................Dec. 12 May* 280 1890 Barringer, Daniel M.............................. Nov. 30 February* 119 1895 Batchelleb, HENRr R.............................. Jan. 15 March 167 BINGHAM Charles E............................. 1923 Bibkett, E. H..................................... Apr. 23 August 394 1913 Bibbell, Robert W................................. Jan. 18 April 214 1926 Blackmar, Don C.................................. June 4 March* 189 1920 Bosworth, T. O.................................... Jan. 18 April 214 1894 Boucher, Arthur S..........................Jan. 6 May 257 1927 Brandenthaler, R. R.............................. Dec. 14 January* 64 1889 Bretherton, S. E............................... Oct. 4 December 581 1911 Brunton, F. K................ .. Aug. 17 1924 Brush, Charles F................................. June 15 September 436 1925 Cameron, Frank N........................May 16 July 349 1891 Chambers, Robert E.............................. May July 348 1908 Clark, J. Murray................................. Dec. 3 August* 407 1883 Clymer, edward T............................. Oct. 13 December 579 1914 Cofpey, George T................................. May 8 July 349 1901 Cooke, L. H....................................... Aug. 23 November 537 1915 Cousins, George W........................ June 30 February* 118 1886 Cowles, A. H...................................... Aug. 13 September 436 1892 Crane, Theron I............................. Nov. 2 December 579 1921 Crowell, Samuel B................................ Dec. 9 January* 64 1907 Curtis, Bracey.................................... Jan. 31 April 215 1895 de Batz, Rene........ ............... January March* 189 1928 Dines, Tyson S.................................... March May 257 1909 Dufourco, R. G............................. January November 537 1920 Ericsson, Eric A.................................. Apr. 4 April* 231 1920 Erlenborn, Willi....................... Nov. 10 March* 189 1888 Farish, John B.................................... Nov. 14 December 580 1891 Ferguson, Vincent........................... Mar. 8 May 257 1917 Finucane, T. R.................................... Mar. 22 February* 118 1921 Foch, Ferdinand................................... Mar. 20 1885 Foucar, Edouard I....................... Jan. 3 March 167 1880 Francklyn, Charles G............................. Jan. 11 April 214 1925 Friedl, Arthur J.............................. July 9 September 435 1894 Fuller, James W. Jr............................... April 4 1876 . Goodale, Charles W.............................. April 11 May 258 1912 Graybill, John..........................Dec. 11 June* 320 1887 Gritzner, F. A.................................. Mar. 26 July 394 1906 Gunther, C. Godfrey.............................. Deo. 26 February* 118 1900 Haggen, Edward A.............................. Apr. 22 October 488 1895 Hall, Benjamin M........................Nov. 19 March* 189 1913 Harper, Walter S................................. Feb. 15 August 394 1921 Hawley, William S................................ Apr. 20 June 298 1920 Herd, Walter ... . . . ..... Aug. 23 September 435 1889 Holt, Marmadtjke B............................... Dec. 26 February* 118 1928 Husk, Albert D .... ................June 9 December 580 1920 Hutchinson, S. Pemberton......................... Feb. 16 April 214 1926 Ivanoff, Constantine L............................ Mar. 7 June 298 1914 Jaeger, Frederick..... .............July 28 October 488 1891 Jennings, Robert E.......................Oct. 30 December 580 1922 Johnson, Homar L................................. Sept. 17 October 483 1927 Johnson, Homer H................................. Mar. 21 May 257 1918 Jones, Jesse L ..... ...............Jan. 22 April 214 1892 Jones, Thomas J................................... June 18 October 488 1883 JoOet, Cavalier H................................. Mar. 29 May 258 1881 Kennedy, John S . . . . ... ..........Apr. 22 August 394 1881 Kennedy,- Hugh.................................... May 23 September 435 1895 Kebvin, James H................................... September October 488 1926 Kkom, L. J........................................ Dec. 24 January* 64 1905 La Follette, Harvey M........................... Sept. 19 November 538 1920 MacDonald, Alexander............................ May August 394 1904 Marengo, Paolo................................... May 257 1925 Maxwell, Allison R............................... May 7 November 538

Jan 1, 1930

Effective control of respirable dust is one of the most serious problems associated with longwall mining in the United States. This report describes the development and laboratory testing of dust collectors for use on double drum shearers. Systems tested included: ? High Capacity Flooded Bed Scrubber ? Water Powered Extraction Cowls ? Water Powered Extraction Drums ? Water Powered spot Scrubbers. The systems were tested using tracer gas in a full-scale model of a longwall shearer face. This report provides a detailed description of the test facility, test methods, and system test results.

Jan 1, 1982

"INTRODUCTION These inspection standards have been prepared for use as a guide for the Federal inspection of anthracite mines. They are a revision of ""Tentative Inspection Standards for Anthracite Mines,"" published as Bureau of Mines Information Circular 7231 in January 1943 and used as a guide for Federal inspections. Numerous changes in the original standards have been made, due in part to recognition of shortages of some types of safety equipment due to the war, in part to need of additional standards to cover certain mine conditions and practices, and in part to conditions not foreseen when the original standards were prepared.Throughout these standards reference is made to determining the methane content of the mine air by using a permissible flame safety lamp. The Bureau has approved various electrical devices for the detection of methane, but it is recognized that new devices for determining the percentage of combustible gases as well as the percentage of oxygen, might be perfected for general use in mines, and therefore it may be necessary to revise certain standards to include the use of such equipment if and when the device is accepted as being permissible.About one-fourth of these standards are marked with an asterisk (*) as being of particular importance in preventing accidents in many coal mines; however, failure to carry out the suggestions made in such of the other standards as are applicable may also lead to loss of life.With continuing change in mining methods, some of these standards may become inapplicable, and further revision will be advisable. Therefore, question regarding these standards and suggestions regarding new standards should be brought to the attention of the Bureau, so that changes may be made from time to time. Numerous changes proposed by mine operators and by State mining departments have been incorporated in these standards."

May 1, 1944

By Ihsan Berk Tulu, Mark Alexander Van Dyke, Deniz Tuncay, Ted M. Klemetti

Bleeder entries are critically important to longwall mining for the moving of supplies, personnel, and the dilution of mine air contaminants. By design, these entries must stay open for many years for ventilation. Standing supports in moderate cover bleeder entries were observed, numerically modeled, and instrumented by researchers at the National Institute for Occupational Safety and Health (NIOSH). The measurements of the installed borehole pressure cells (BPCs), standing support load cells and convergence meters, and roof extensometers are presented in this paper in addition to the numerical modeling results and visual observations made by the NIOSH researchers in the bleeder entries. The results include the effects of multiple panels being extracted in close proximity to the instrumented site as well as over one and a half years of aging. As expected, standing supports closer to the longwall gob showed the greatest load and convergence. The roof sag appeared generally independent of the proximity to the longwall gob. The BPC readings were driven by both the proximity to the gob and the depth into the pillar. The results of this study demonstrated that the entry roof can respond independently of the pillar and standing support loading. In addition, the rear abutment stress experienced by this bleeder entry design was minimal. The closer the mine development, pillar, or supports are to the gob, the greater the applied load due to rear abutment stress.

Jan 7, 2021

The 73rd Regular Meeting of the Rocky Mountain Coal Mining Institute convened at The Mark Conference Center, Lionshead Village, Vail, Colorado, and was in session at 10:00 a.m. Past President, Robert W. Wilson, President and General Manager, K&P, Inc., Golden, Colorado, called the meeting to order. The membership was asked to stand and pledge allegiance to the flag. As your immediate past president, it is my pleasure to have the responsibility of introducing our current President. But before I tell you about Ralph, I would like to make the following brief reflection, which I feel very strongly about: In these days of so much negativism toward our coal industry by so many people, we all must remember one thing as we go about producing energy for our country. Coal mining is just as American as the American hamburger, the American hot dog, and just as American as the flag to which we just pledged allegiance.

Jan 1, 1977

By AIME AIME

AMONG the recent mining and metallurgical developments in England great interest has been shown in the development of an iron-ore field covering 26,0.00 acres in Northamptonshire, containing 500,¬000,000 long tons of ore; and the erection at Corby, by Stewarts & Lloyds, of a modern basic bessemer steel plant and tube works. The entire project was planned to cost about £3,300,000. Many improvements have been made in the varied equipment that is being installed, some of which has set mew records for massiveness. There is, for instance, a new roll crusher, which has been manufactured by Hadfields, Limited, of Sheffield, the largest ever built in England, and weighing 130 tons. This machine, shown in Fig. 1, as erected at the Hadfields shops, is primarily designed to take blocks of iron ore as they come from the steam shovel. The maximum size is 54 by 48 by 36 in., hut occasional pieces slightly larger than this may be accommodated. The capacity is upwards of 500 tons per hour, the product passing to a secon-

Jan 1, 1934

By W. M. Pytel

The applicability of the beam theory in analysis of roof- pillar-weak floor interaction in partial extraction room-and-pillar mining is presented. The mine structure is modeled as an equivalent multi-indeterminate overburden elastic beam supported by elasto-plastic pillars; resting on a viscoelastic layer of immediate weak floor strata underlain by a competent rock mass. The developed analytical model was initially utilized to conduct sensitivity analyses of different variables affecting the mining system, such as the deformability of coal and weak floor strata, thickness of weak floor strata, number of pillars in a panel, width of pillars, width of panel etc. These analyses were then extended to three overburden strata - coal pillar - floor strata lithologies typical of active coal mining areas in Illinois.

Jan 1, 1989

By George S. Rice

"INTRODUCTION During the past 4 or 5 years the frequent occurrence of bumps in coal mines of the Cumberland field, in Harlan County, Ky., and Wise County, Va., has caused much apprehension among miners and mining officials of that region.These bumps have caused many deaths and injuries, and have been increasing in frequency. Eight men were killed and a number injured by bumps in the first 4 months of 1934. Their unpredictable occurrence and the usual absence of any preliminary warning tremors or sounds, such as ordinarily precede a large fall of roof, cause fear of other bumps and impair the morale of mine workers.Acknowledgments This report on bumps in coal mines of the Cumberland coal field of Kentucky and Virginia is based on an investigation made at the urgent request of .the Harlan County Coal Operators Association, through James F. Bryson, director of safety of the association, to the Director of the United States Bureau of Mines, following a series of disastrous bumps in. Harlan County, Ky., and Wise County, Va. The request was granted and the writer detailed to undertake the investigation, which was made in June 1934.The officials of certain operating companies in the Cumberland field gave every facility for examining the conditions accompanying bumps in their mines. The writer is most grateful to them for the courtesies shown; to J. F. Bryson, to J. F. Davies, district engineer, Safety Division, U. S. Bureau of Mines, who accompanied the writer throughout his trip to the vari¬ous mines and gave him much assistance and detailed information regarding the occurrence of bumps; and to Dr. David White for reviewing the geological descriptions,Definition of Bumps ""Bumps"" are phenomena comparatively rare in the coal fields of the United States and, for that matter, in the coal fields of the world, because for their occurrence certain exceptional natural conditions are required strong, massive strata of sandstone or conglomerate above the coal and a fairly strong floor, as will be described in detail later."

Jan 1, 1935

By E. C. Potter

FUEL-OIL was first substituted for coal at these works in September, 1888. It was first applied in the converting-department to the battery of boilers, consisting of 14 tubular boilers, 16 feet in length by 5 feet in diameter. To operate these boilers with coal for 24 hours required 14 strikers, 3 ash-wheelers, 6 men unloading coal, and 2 water-tenders, making a total of 25 men. With fuel-oil the same boilers require for the same period 2 water-tenders and 4 men to attend to the burners, making a total of 6 men. This gives a saving of 19 men, which, at an average of $2 per day each, amounts to $38 per day. Comparing the consumption of oil with that of coal, we find that for the week ending January 5, 1889, with an ingot output of 6403 tons, 2731 barrels of fuel-oil were used as against a necessary consumption of coal for the same work of 848 tons, showing 3.22 barrels of fuel-oil to be equivalent to one ton of Indiana block-coal. Figuring oil at 60 cents per barrel, and coal at $2.15 per ton, we have as the cost of oil $1.93, as against $2.15 for its equivalent in coal. In December, 1888, the rail-mill battery of 26 boilers, of the same dimensions as those in the converting-department, was equipped for fuel-oil. For the week ending January 5, 1889, with a rail out-put of 5208 tons, 5987 barrels of oil were consumed, as against a necessary consumption of coal, to do the same work, of 1805 tons, showing 3.31 barrels of fuel-oil to be equivalent to one ton of Indiana block-coal, which at the costs named above would show $1.98 worth of fuel-oil to he equal to $2.15 worth of coal. The labor required to operate the rail-mill boilers for 24 hours, with coal as fuel,is: 26 stokers, 4 water-tenders, 6 ash-wheelers, 12 men unloading coal; total, 48 men. With oil as fuel, the same work requires 4 water-tenders and 6 men to attend to the burners; total, 10 men; a saving over coal of 38 men in 24 hours, which, at an average price of $2 per day, would be $76 per day. In the brief experience we have had with oil as fuel, we find that the efficiency of the boilers is somewhat increased and the repairs are

Jan 1, 1889

By Frank Armstrong

ALL the mining machinery of the Penn Iron Mining Co. has been operated by electric power for several years and when another shovel for stockpile loading was required the advantages of an electric shovel were naturally considered. After considerable study, serious objections suggested themselves the use of a shovel operated directly by electrical apparatus by reason of the complicated control, severe service on the motors FIG. 1.-ELECTRO-HYDRAULIC SHOVEL FIG:. 2-THE SHOVEL AS IT WAS OPERATED CINDER CONSTRUCTION. THE FIRST YEAR. and the heavy surges of current required from the line. It was finally decided to construct an electro-hydraulic shovel using water under pressure to perform all the necessary operations except that of propelling, for which a separate motor was best suited. A car body with boom, dipper handle and dipper of late design, but without any of the steam machinery, was purchased. A motor-driven centrifugal pump, a pressure tank, an air tank, a small air compressor and water cylinders with plungers, pistons and valves, were installed in place of the; steam equipment. Fig. 1 shows this shovel under construction and Fig. 2 shows it as it was operated during the first year, the summer of 1914. The large tank at the back of the car, in Fig. 1, carried air under

Jan 2, 1916

The 68th Regular Meeting of the Rocky Mountain Coal Mining Institute convened in Manor Vail Lodge, Vail, Colorado, and was in session at 10:00 a.m. The meeting was called to order by Past President Max A. Robb, Vice President and General Manager, U.S. Fuel Company, Hiawatha, Utah. Mr. Robb welcomed the members and guests and was pleased with the large attendance. He then introduced President Joseph E. Ward, former District Man- ager, Denver Office, Coal Division, Joy Manufacturing Co. (Retired). A brief biography follows: Mr. Ward is a transplanted Westerner, having spent the greater part of his life in the Eastern and Southern areas of this country. In 1927, he graduated from what was then the Carnegie Institute of Technology in Pittsburgh, Pa., with a B.S. degree in Mining Engineering. He dropped out of school for a period between his Junior and Senior years and worked in the coal mines in order to obtain sufficient money to complete his education. Practically all his adult life since graduation, has been spent in or around the coal mines in this country. After graduation, he worked the next 15 years of his life as an underground supervisor, first for the Hudson Coal Co., in Scranton, Pa. and later for the U.S. Steel Corporation in Birmingham, Alabama. He then went into sales, selling basically to the coal mine industry and other mining operations. The last 13 years of his business career were spent as a district manager for Joy Manufacturing CO., 10 years of which were in the Coal Division of their Denver office, covering the Rocky Mountain area. He retired in August 1970 but still retains an active interest in the Rocky Mountain Coal Mining Institute and the Rocky Mountain Coal Industry it supports. He is a widower, his wife, Thelma having died in July 1970. He has two children and six grandchildren.

Jan 1, 1972

By MUSTAFA ERKAYAOGLU, ENVER YILMAZ

Coal is still a part of energy generation worldwide and has a significant role in the sustainable development of countries. The amount of shallow coal deposits is getting scarce, making efficient underground mining operations crucial for both local and global economies. In underground mining operations, longwall mining is a commonly utilized method to extract deep coal deposits. One of the leading engineering goals in longwall mining is increasing the efficiency of the system by investigating the effects of operational factors on equipment. This paper investigates the shearer performance for a longwall top coal caving operation by discrete event simulation that includes modeling the double-drum shearer, belt conveyors, stage loader, and armored face conveyors (AFC) to evaluate system performance by considering the amount of daily coal production of the shearer. As a result, the most influential factor on mine production is determined and a data-based framework is developed. This study suggests a framework for data collection, data analysis, and the interpretation of the operational data to evaluate the primary production unit’s performance. The models developed for the face coal extraction operations in a longwall top coal caving (LTCC) mine have a bi-directional cutting system and can be implemented in other operations readily.

Jul 2, 2021

By Donald A. Ranta

Every mineral project or mine is based on a geologic entity-an ore (mineral) deposit. A well-defined mineral deposit and its associated geologic characteristics are the only aspects of a project that cannot be altered. Mine plans can be modified to exploit the deposit using alternative approaches and yielding similar results. A variety of processing methods also are often available producing generally comparable results. Major modifications can be made to other aspects of the project without substantially changing project economics. However, all engineering and metallurgical aspects of a mine must be accommodated to the spe¬cific location and geologic characteristics of the deposit. Geologic data and interpretations form the foundation for both mine evaluation and mine production by providing esti¬mates of reserves and essential information for mine planning and process design or control. Proper geologic work requires a keen awareness of and an ability to anticipate the technical requirements of geotechnical engineers, hydrologists, mining engineers, metallurgists, and other specialists. Geologists are inte-

Jan 1, 2008

The meeting was called to order by the President, Mr. B. J. Matteson, in Dining Room No. I of the Albany Hotel, at 10 a. in., with thirty members present. After an address of welcome by the President, the Convention proceeded to business. First on the program was the reading of the minutes of the' previous meeting, by" the Secretary.' There being no alterations or amendments they were approved as read. A motion was regularly moved and carried that the Secretary provide membership cards to be mailed, or presented, to the members upon payment of dues in lieu of the receipt which has heretofore been used since the organization of the Institute. Mr. R. A. McAllister then presented his paper, the subject, being: "Mine Haulage." Mr. Robert A. Marshall had prepared a paper upon the subject of "Efficiency in Shot Firing," but as he was unavoidably absent, it was read by Mr. Sam Andrews. At the conclusion of the reading of Mr. Marshall's paper, Mr. Andrews presented his own *paper: "Some Facts About Coal Mining." As Mr. George A. Brown was unable to be present, the President requested Mr. R. S. Morton to read his paper, subject: "Flexoid Tubing and Its Application to Coal Mines as a Means of Temporary Ventilation." There being no further business 'the meeting adjourned.

Jan 1, 1921

By Doyle A. Ellerbruch

An FM-CW microwave system was investigated for measuring coal layer thickness. Measurements were made in three different mines near Pittsburgh, Pennsylvania, near Fairview, West Virginia, and near Coffeen, Illinois. Microwave frequencies in the range 1-2 GHz were used to measure samples up to 55 cm thick. All samples were backed with a naturally occurring shale. Measurements were also made on coal and shale samples compounded in the laboratory at the Bureau of Mines Pittsburgh Mining and Safety Research Center near Bruceton, Pennsylvania. The results indicate that layer thickness can be determined in most cases, although large anomalies may, in some cases, produce misleading results. Many anomalies that were detected with the FM-CW system were verified visually by drilling into the coal layer. The dielectric constant of coal apparently varies significantly within a coal seam. The form of the output signals from the FM-CW system seem to simplify the data interpretation and analysis process as compared to the manually swept microwave system used previously. It appears that this technique has the potential of measuring changes in the dielectric constant of a coal seam and providing an output that can be used for real-time corrections in layer thickness; measurement.

Jan 1, 1976